Why does unix 'nohup' not work for me.

I use Ubuntu and previously (few years ago) used: 'nohup ...job... &' to run a long job, exit, then later login to see the job in progress or completed. It worked back then, but not now! Maybe AWS now handles disconnects differently. I tried many suggestions on internet (eg: disown) but all failed. EDIT: setsid also did not work.